The overall objective of this proposal is to determine the extent to which age-related changes in sympathetic nervous system (SNS) function, sensitivity to the metabolic effects of insulin, and salt-sensitivity of blood pressure contribute to hypertension in the elderly. We hypothesize that the compensatory mechanisms which normally allow adaptation to these age-related changes are impaired in older hypertensives. We further hypothesize that an improvement insulin sensitivity and decrease in blood pressure following a six month aerobic exercise training program will be associated with alterations in salt sensitivity, SNS function and renal hemodynamics (specifically a decrease in filtration for sodium).